My problem is different... my device is always on (little blue light is on) and on/off switch don't works. I try your power change cicle (30 min, 10 min, same hours) but nothing has changed. I try with reset (my device have a little hole on the back for press the reset switch) but it's the same.

I see your video, but my problem is how I can remove an aluminium cover? I remove two little screws, but after I can't raise.

the same thing happened with me when i wanted to install a firmware, a blue light was always on. to rsove it you must remove the 2 screws then push the cover down it may need some force to do it, then disconnect the wire of the battery and reconnect it.